There has been a long-felt need for a fastener which overcomes some of the problems associated with the snap button fastener, such as the DOT.RTM. fastener found in service on boat covers and many other canvas and the like articles. Some of the problems associated with the conventional DOT.RTM. type fastener are:
(a) There is a critical tolerance requirement that makes snap buttons unpredictable as to holding strength. Since snap buttons operate by the critical mating of two dimensions, they are subject to great variation in holding strength because of variations in dimensions or tolerances in the spring ring and male stud parts. Because most snap button fasteners are sheet brass made on progressive dies, they are soft enough to be deformed during usage and this can render them inoperable or change their holding characteristics, making them either too loose or too tight. PA1 (b) Weathering of the parts of snap button fasteners can make the buttons too tight to pull apart, especially in hostile environments like salt water, industrial pollution and the like. PA1 (c) Limited strength due to manufacture from sheet brass or molded plastic construction renders the conventional snap button fastener of limited utility when confronting heavy loads. PA1 (d) There is considerable difficulty in operating such a fastener when either the male or female side of the fastener is covered with foreign matter such as dust, mud, ice, grease, etc.
In the prior art the following patents depict fastening devices in which a stud and/or eyelet must be deformed as a necessary condition precedent to latching or locking the stud and eyelet together: U.S. Pat. Nos. 991,156; 2,397,801, 2,986,790; 3,213,507; 3,349,451; 3,416,200; 3,729,780 and 2,786,982.